Quick answer: Scientific or technological uncertainty exists where it is not readily deducible by a competent professional whether something is scientifically possible or technologically feasible, or how to achieve it in practice. It is the central test for R&D under the BIS Guidelines, covering system, component and existence uncertainty, but excludes commercial, regulatory or financial uncertainty.
What is scientific or technological uncertainty?
Scientific or technological uncertainty exists where knowledge of whether something is scientifically possible or technologically feasible, or how to achieve it in practice, is not readily available or deducible by a competent professional working in the field. It is the central test for research and development under the BIS Guidelines: a qualifying project must seek an advance through the resolution of such uncertainty. Commercial, regulatory or financial uncertainty does not count.
How does HMRC define scientific or technological uncertainty?
HMRC guidance on technological uncertainty is at CIRD81300 of the CIRD Manual, cross-referenced to paragraphs 12 to 18 of the 2023 BIS Guidelines. HMRC distinguishes system uncertainty, where individual components are known but their integration is not, from component uncertainty and from uncertainty as to the very existence of a solution. All three can support a valid R&D claim.
What does scientific or technological uncertainty look like in practice?
A machine-learning company attempts to predict a specific industrial outcome from streaming sensor data. Published techniques address adjacent problems but none covers the full data pipeline and feedback latency required. A competent professional cannot readily deduce the architecture needed, and iterative experimentation is required. This is genuine scientific or technological uncertainty.
What is the difference between system, component and existence uncertainty?
A robotics company integrating three well-understood subsystems - vision, motion planning and grip control - into a single real-time pipeline faces system uncertainty even though each subsystem individually is well documented, because the combined latency and failure-mode behaviour cannot be predicted in advance. If the £220,000 spent resolving that integration problem is genuine R&D, it qualifies for the merged scheme’s 20% credit - £44,000 - regardless of whether any single component was itself novel. See eligible R&D activity for the wider boundary HMRC applies.
How is technological uncertainty different from ordinary difficulty?
HMRC draws a sharp line between technological uncertainty and ordinary engineering difficulty. Work that is merely time-consuming, expensive, or requires skilled staff - but where the outcome could be confidently predicted in advance based on the current state of the art - is not R&D, however hard it was to build. The BIS Guidelines and CIRD Manual both use this distinction to separate genuine R&D from routine, if difficult, development. HMRC caseworkers are trained to probe for this distinction specifically during enquiry, often asking the claimant to name the published state of the art the project was measured against - a question that a genuinely uncertain project can answer directly, and a merely difficult one usually cannot.
Frequently asked questions
No - R&D can qualify even if the project ultimately fails to resolve the uncertainty or the company abandons the work; what matters is that genuine technological uncertainty existed and a systematic attempt was made to resolve it, not that the attempt succeeded.
System uncertainty arises when individual components are known but their integration is not; component uncertainty concerns whether a specific component itself can be built; existence uncertainty concerns whether a solution exists at all. All three can support a valid R&D claim.
Technological uncertainty means a competent professional cannot predict the outcome in advance based on the current state of the art. Ordinary difficulty means the outcome is predictable but the work is time-consuming, expensive or requires skilled staff. Only genuine uncertainty, not mere difficulty, qualifies as R&D.
Commercial, regulatory or financial uncertainty does not qualify, even if it makes a project risky. HMRC's test is specifically about scientific or technological uncertainty: whether something is scientifically possible or technologically feasible, and how to achieve it in practice.